Melt spinning apparatus with removable spinning assembly



Filed Feb. 10, 1953 J. W. PHIPPS MELT SPINNING APPARATUS WITH REMOVABLE SPINNING ASSEMBLY July s, 1958 I FIG.

INVENTOR JOHN W/LDEY PH/P P5 MW,M7 W

AT TORNEYS MELT SPINNING APPARATUS WITH REMOVABLE SPINNING ASSEMBLY John W. Phipps, St. Albans, England, assignor to Imperial Chemical Industries Limited, a corporation of Great Britain Application February 10, 1953, Serial No. 336,159

Claims priority, application Great Britain February 19, 1952 1 Claim. (Cl. 18-==-B) This invention relates to improved apparatus for melt spinning.

In apparatus at present used for melt spinning, it is common practice to melt the filament forming material,

e. g. by means of a hot grid, and to pass the molten material, e. g. by means of a gear pump, through a filter pack to the spinneret in what is known in the art as a spinning head. The filter pack and spinneret form a removable unit which is changed frequently for cleaning and replacement of the components. It is therefore necessary for this unit, referred to in the art as the spinning pack, to be jointed to the spinning head, and consequently the joint must be able to withstand the pressure of molten material coming from the gear pump. The making of this joint is a complicated and lengthy operation during which the spinning apparatus must be stopped.

According to the present invention, I provide an improved melt spinning apparatus wherein the pump and the spinning pack form a unit, to which the molten filament forming material is fed from the melting zone, said unit being removable from the spinning apparatus for cleaning and replacement of the components.

The fact that the pump and spinning pack are removed together means that only one joint needs to be broken for cleaning or replacement and that joint is on the inlet side of the pump. All the joints in the spinning pack and between the pump and the pack can be tightened beforehand in an assembly room and the time for which the spinning apparatus is stopped to enable the spinning pack to be changed is thus greatly reduced.

The removable unit, comprising pump and spinning pack, is supported on and located by shoulders or ledges within the spinning apparatus and is secured in position by a single clamping screw, the tightening of which is sufiicient to make the joint, connecting the inlet side of the pump to the melting zone, fluid tight. On fitting such a unit into place there are no awkward upward fitting bolts to be inserted, as when fitting a spinning pack of the prior art, the removable pump and spinning pack unit is merely slipped into place and held there by the one clamping screw. Thus the operation of changing the spinning pack is greatly simplified and expedited.

During the removal of the pump and spinning pack unit, the flow of molten material from the melt head must be stopped. This can be done simply by incorporating a stop-cock in the feed line.

It will be appreciated that the drive to the pump, in the apparatus of this invention, must be made and positioned to allow removal of the pump/ spinning pack unit. This is done by driving the pump by a shaft which can be retracted during the withdrawal of the unit.

The attached drawing illustrates but does not limit the scope of the invention.

The drawing is a diagrammatic section through part of a spinning apparatus showing the removable pump pack "ice unit supported on the ledge 2 in the spinning head 3. A duct 4 leads molten polymer from a melting unit (not shown) via a cock 5 and a gland 6 to a spinning pump 7. The joint is made fluid tight by pressure exerted by the clamp screw 8. Heating of the apparatus is obtained by circulating hot vapour through the spaces 9 and the heat is retained by the lagging 10. The pump is driven by the retractable shaft 11 through the key 12. A duct 13 connects the pump outlet with the sand pack 14 resting on a gauze 15 supported by a rigid plate 16. A spinneret 17 is held in place by a support plate 18 and items 15, 16, 17 and 18 are held rigidly in place in the removable unit by a ring of bolts 19.

The drawing also shows a removal tool 20 which fits into the socket 21 in the removable unit.

When an apparatus of the type shown in the drawing is in use the clamp screw 8 is locked so that pressure is exerted on the joint 6. When it is desired to remove the removable unit for cleaning or dismantling, the stop cock 5 is closed, the clamp screw 8 is loosened and the shaft 11 withdrawn. Removal of the lagging 10A enables the whole unit to be lifted from the spinning head by means of the removal tool 20.

If spinning is to be continued, a replacement unit is lowered onto the ledge 2, the clamp screw 8 is tightened, the shaft 11 inserted, the lagging replaced and the stop cock opened. The ring of bolts 19 have already been tightened up before fitting the unit and all joints round the pump have been similarly dealt with. This replacement of one unit by another can be done in a matter of seconds.

The removable unit in the drawing is lifted upwards for removal. It will'be appreciated that in different types of apparatus the unit may move sideways or if desired downwards for removal and may be supported otherwise than on a ledge. Similarly the clamp screw may be replaced by any other known locking means and the feed duct and the pump driving shaft fitted in a wide variety of ways.

Many methods of melting the filament forming material are known, e. g. melting on a hot grid or in a screw extruder or in a combination of the two. The apparatus of this invention may be used in conjunction with any melting apparatus.

The apparatus of this invention is particularly suitable for use where one melting unit feeds many spinning heads. Any spinning head can be taken out of action by stopping the flow of molten polymer thereto and the ease with which the removable unit of our invention can be taken out and replaced is a great asset.

While it is preferred that the pump used is a gear pump, other pumps may be used if desired. For example for the extrusion of certain filaments, it may be possible to use a screw pump.

The apparatus of this invention may be used in melt spinning any thermoplastic filament forming material. It is particularly suited to the melt spinning of those materials with highly viscous melts e. g. nylon and the highly polymeric polymethylene terephthalates, since these materials have a great tendency to leak at any joints, under the high pressures used in extrusion.

Using the apparatus of this invention I have found that the temperature of the spinning pack components, particularly the spinneret, and the gear pump can be kept uniformly hot without difiiculty. The fact that the pump can be completely enclosed by lagging prevents heat losses which have occurred with apparatus of the prior art.

What I claim is:

A melt spinning apparatus comprising a spinning unit, means defining an upwardly opening well for remov- 3 ably receiving and supporting said unit, means having communication, and means detachably connected with an outlet communicating with said well for supplying said pump for driving the latter. molten filament forming material to said unit, means sub- References Cited in the file of this patent stantially surrounding said well for heating the unit supported therein, said spinning unit comprising a pump 5 UNITED STATES PATENTS for pumping'th'e material from said supplying means 2,217,743 Greenewalt Oct. 15, 1940 and a spinning pack through which the materialis pumped 2,341,731 MacGrego-r et al. Feb. 15, 1944 by said pump, said unit providing an inlet for said 2,601,642 Stammer et al June 24, 1952 pump, clamping means for securing said unit to said Well 2,692,405 Gayler Oct. 26, 1954 defining means with said inlet and outlet in fluid-tight 10 2,707,306 Weber et al. May 3, 1955 

